Image forming apparatuses such as printers and copiers are usually configured such that it is possible to open and close a part of their housing frame, and thus the inner portion is accessible when necessary, for example, when changing supply products such as ink and toner, when removing printing paper jammed inside the apparatus, or when performing maintenance.
Inside the apparatus, a high voltage is used for transfer, a fixing portion is heated to a high temperature, and various types of functional components rotate and move complexly in conjunction with one another. Therefore, an opening and closing member is provided with an interlock switch to monitor a state of opening and closing the opening and closing member, for the purpose of preventing trouble caused when the operator carelessly accesses inside the apparatus.
However, in order to improve work efficiency when changing supply products, handling jammed materials, and performing maintenance, image forming apparatuses such as printers and copiers tend to have a large opening portion. Accordingly, the opening and closing member is large, and it is necessary to operate a plurality of lock member sets in order to close the opening and closing member, so that the operation is significantly complicated.
In order to address the above-described problem, for example, a lock mechanism has been proposed in which engagements of a plurality of secured hooks on a door member with engagement portions on a mainframe are simultaneously released by operating one button and in which the plurality of secured hooks on the door member can be simultaneously engaged with the engagement portions on the mainframe by closing the door member (see JP H06-45025U (Paragraph Nos. [0015] to [0024], and FIG. 12), for example).
In this configuration, the plurality of secured hooks are pivotably supported with respect to the door member, and the engagement portions for securing the secured hooks are attached to the mainframe via a rotatable shaft.
However, in the configuration described in JP H06-45025U, the number of the components is large because the secured hooks and the engagement portions constituting the lock mechanism are formed separately from the door member and the mainframe, and pivoting portions and rotating portions make the configuration significantly complex, so that there is the problem that the apparatus becomes large and the manufacturing cost is high.
The present invention was made in view of the above circumstances, and it is an object thereof to provide a lock mechanism, for an opening and closing member, that has a good operability and a simple configuration, and an image forming apparatus provided with the lock mechanism.